The Brennan Surname Distribution Map shows all of the Brennans (in yellow) documented in County Mayo, Ireland when the Griffith's Valuation was conducted between 1855 and 1857. Brennans were noted in 38 different Civil Parishes in County Mayo at that time. Note that in the map above, Brennans are only present in the lower portion of Islandeady (27) that falls in Burrishoole Barony.
1. Achill | 2. Addergoole | 3. Aghagower |
4. Aghamore | 5. Aglish | 6. Annagh |
7. Ardagh | 8. Attymass | 9. Balla |
10. Ballinchalla | 11. Ballinrobe | 12. Ballintober |
13. Ballyhean | 14. Ballynahaglish | 15. Ballyovey |
16. Ballysakeery | 17. Bekan | 18. Bohola |
19. Breaghwy | 20. Burriscarra | 21. Burrishoole |
22. Cong | 23. Crossboyne | 24. Crossmolina |
25. Doonfeeny | 26. Drum | 27. Islandeady |
28. Kilbeagh | 29. Kilbelfad | 30. Kilbride |
31. Kilcolman | 32. Kilcommon | 33. Kilconduff |
34. Kilcummin | 35. Kildacommoge | 36. Kilfian |
37. Kilgarvan | 38. Kilgeever | 39. Killala |
40. Killasser | 41. Killedan | 42. Kilmaclasser |
43. Kilmainebeg | 44. Kilmainemore | 45. Kilmeena |
46. Kilmolara | 47. Kilmore | 48. Kilmoremoy |
49. Kilmovee | 50. Kilturra | 51. Kilvine |
52. Knock | 53. Lacken | 54. Manulla |
55. Mayo | 56. Meelick | 57. Moorgagagh |
58. Moygawnagh | 59. Oughaval | 60. Rathreagh |
61. Robeen | 62. Rosslee | 63. Shrule |
64. Tagheen | 65. Templemore | 66. Templemurry |
67. Toomore | 68. Touaghty | 69. Turlough |
A. Castlemore (transferred to Co. Roscommon 1898) | B. Kilcolman, Costello Barony (transferred to Co. Roscommon 1898) |